U.S. patent number 4,487,330 [Application Number 06/568,552] was granted by the patent office on 1984-12-11 for trim clamp assembly.
This patent grant is currently assigned to Square D Company. Invention is credited to Dennis J. Grover, David W. West.
United States Patent |
4,487,330 |
Grover , et al. |
December 11, 1984 |
Trim clamp assembly
Abstract
A compact and economical clamp assembly for securing a cover
plate to an open front electrical panelboard box having mounting
flanges. The assembly includes an insulating sleeve surrounding a
screw, both of which extend through a hole in the cover plate. The
screw has a slotted head, a reduced diameter tip and an
intermediate threaded portion. The sleeve has a recess to receive
the screw head and a pair of diametrically opposed slots extending
from a mid portion of the sleeve to one end. The screw is
positioned so that the slots of the sleeve overlap a substantial
portion of the threaded portion of the screw. A nut, threadingly
engaged with the screw, has two wings which protrude through the
respective slots of the sleeve. A clamp member, having a camming
end and a clamping end, is pivotally connected to the wings. A
torsional spring biases the camming end of the clamp member into
contact with the cover. As the screw is turned in a predetermined
direction, the nut advances toward the cover, drawing the clamping
end to the cover to secure the cover plate against the mounting
flange of the box.
Inventors: |
Grover; Dennis J. (Kokomo,
IN), West; David W. (Naperville, IL) |
Assignee: |
Square D Company (Palatine,
IL)
|
Family
ID: |
24271756 |
Appl.
No.: |
06/568,552 |
Filed: |
January 5, 1984 |
Current U.S.
Class: |
220/324; 220/3.8;
361/641; 361/646 |
Current CPC
Class: |
F16B
2/185 (20130101); H02B 1/06 (20130101); F16B
5/0642 (20130101) |
Current International
Class: |
F16B
2/02 (20060101); F16B 2/18 (20060101); F16B
5/06 (20060101); H02B 1/015 (20060101); H02B
1/06 (20060101); B65D 045/16 () |
Field of
Search: |
;220/324,3.8,342
;361/356,360 ;174/66,67 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hall; George T.
Attorney, Agent or Firm: Golden; Larry I. Guttman; Richard
T.
Claims
We claim:
1. An adjustable clamp assembly on a cover plate for clamping the
cover plate to a box having a mounting flange comprising:
a sleeve having a longitudinal axis extending outward from said
cover plate, said sleeve including a plurality of slots directed in
generally perpendicular relationship to said cover plate;
a screw positioned along said longitudinal axis of said sleeve;
a nut threadingly engaged with said screw, said nut including a
plurality of wings extending radially outward from said
longitudinal axis, each wing extending through a respective one of
said slots whereby rotation of said nut with respect to said sleeve
is prevented;
a clamp member pivotally associated with said nut and including a
first end portion and an opposite second end portion;
biasing means for biasing said clamp member to a first position
wherein said first end portion is engaged with said cover plate and
said second end portion is spaced substantially away from said
cover plate, said second end portion being drawn against the bias
of said biasing means toward said cover plate in response to the
turning of said screw which draws the nut toward the cover
plate.
2. A clamp assembly as claimed in claim 1 wherein said sleeve
comprises a nonintegral part of said cover plate and includes a
head at one end and a pair of diametrically opposed slots beginning
adjacent said head and extending away from said head throughout the
entire length of the sleeve.
3. A clamp assembly as claimed in claim 2 wherein said sleeve
includes a nib provided on the underside of said head and said
cover plate includes portions defining a notch which receives said
nib and restrains rotation of said sleeve with respect to said
cover plate.
4. A clamp assembly as claimed in claim 2 wherein said screw
includes a slotted screw head at one end, an intermediate threaded
portion and a reduced diameter tip at the opposite end.
5. A clamp assembly as claimed in claim 4 wherein said head on said
sleeve includes portions defining a recess which receives said
slotted head of said screw, said clamp assembly further including a
fastener secured to the tip of said screw to retain said nut on the
screw.
6. A clamp assembly as claimed in claim 1 wherein said clamp member
comprises a pair of legs joined at a first side of and also joined
at a second side of each leg including an opening in registration
with one another, said nut including a pair of diametrically
opposed wings, each of said wings extending through a respective
one of said openings.
7. A clamp assembly as claimed in claim 6 wherein said biasing
means comprises a tortional spring member.
8. A clamp assembly as claimed in claim 7 wherein said tortional
spring comprises a pair of coil portions each respectively
surrounding a wing, a generally U-shaped bridging portion having a
pair of opposite legs and a connecting portion, said connecting
portion abutting against said cover, and an arm extending from the
opposite end of each coil, said arm including a bent tang portion
engaged with the underside of said clamp member.
9. A clamp assembly as claimed in claim 8 wherein said sleeve is
formed from an insulating material.
10. A clamp assembly as claimed in claim 8 wherein said clamp
member legs each comprising a rounded camming surface at the first
end portion which tapers upward towards the second end portion.
11. A clamp assembly as claimed in claim 10 wherein said clamp
member includes a cut-away portion between said legs and between
said first end portion and said second end portion, dimensioned to
accommodate the sleeve.
12. A clamp assembly as claimed in claim 11 wherein said clamp
member is generally U-shaped in cross section.
13. An adjustable clamp assembly for clamping a cover plate having
a first surface, a second surface, and an opening therethrough, to
an open front box having a mounting flange, said clamp assembly
comprising:
a sleeve having a longitudinal axis generally perpendicular to said
cover plate, said sleeve having a portion extending through said
opening and generally outwardly from said first surface and
including a plurality of slots in said extending portion having a
component in the longitudinal axial direction;
a screw having a head and a middle threaded portion, said screw
extending from the head which is located in engaging relationship
with the second surface through the cover plate to the threaded
portion located generally within said sleeve extending portion,
said screw being approximately positioned along said longitudinal
axis of said sleeve;
a nut threadingly engaged with the threaded portion of said screw,
said nut including a plurality of wings extending radially outward
from said longitudinal axis, each wing extending through a
respective one of said slots whereby rotation of said nut with
respect to said sleeve is prevented;
a clamp member pivotally associated with said nut and including a
first end portion and an opposite second end portion; and
biasing means for biasing said clamp member to a first position
wherein said first end portion is engaged with said cover plate and
said second end portion is spaced substantially away from said
cover plate, said second end portion being drawn against the bias
of said biasing means toward said cover plate in response to the
turning of said screw which draws the nut toward the cover
plate.
14. A clamp assembly as claimed in claim 13 wherein said clamp
member comprises two legs, each with first and second ends and an
opening, said legs located tangential to said slots and joined at
their respective first ends by the first end portion and at their
respective second ends by the second end portion, said sleeve
including a pair of slots, and said nut including a pair of
diametrically opposed wings, each wing extending through a slot and
through a respective opening in said legs.
15. A clamp assembly as claimed in claim 14 wherein said sleeve
includes a stop surface portion within said sleeve approximately
perpendicular to said longitudinal sleeve axis adapted to prevent
the screw head from passing into the sleeve extended portion.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to clamping members and more
particularly to a clamp assembly for securing a front trim panel to
an open front electrical panelboard box.
2. Description of the Prior Art
Panelboards have various types of clamps for clamping exterior trim
and door assemblies in position with respect to the open front
boxes of electrical panelboards and telephone cabinets.
Exemplary of such a clamp assembly is that disclosed by U.S. Pat.
No. 4,131,932, issued Dec. 26, 1978 to Brumfield, Jr. et al.
Preferably, the clamp members are adjustably tightened against the
back of the side flanges of the box to draw the cover snuggly
against either an adjacent wall or against the front side of the
side flanges to eliminate the need for adjustment of the interior
trim assembly. Furthermore, the clamp assemblies must be adjustable
to a position which will enable ready positioning of the cover
against the box. The relatively large clamp assemblies disclosed in
Brumfield, Jr. et al rotate about an axis perpendicular to the
cover to enable the cover to be positioned against the box and are
then rotated back to their original position to enable tightening
of the clamp members against the flange of the box.
There is a need for a simpler, more compact, economical clamp
assembly especially for use in some of the more narrow panelboards
which have less space between the door opening on the cover and the
side of the box with which the cover is engaged.
SUMMARY OF THE INVENTION
The present invention provides a simple, compact and economical
clamp assembly for use in securing a cover plate to a box having
front mounting flanges over which the cover is positioned.
The clamp assembly includes a cylindrical sleeve member which
extends through an opening in the cover plate. The sleeve has a
head at one end and a pair of diametrically opposed slots extending
away from the head from a point adjacent the head throughout the
length of the sleeve. A screw having a slotted head at one end, an
intermediate threaded portion and a reduced diameter tip at its
opposite end is positioned along the longitudinal axis of the
sleeve with the screw head received in a recessed portion provided
in the head of the sleeve. A double winged nut having its wings
extending respectively through each of the slots in the sleeve is
threadingly engaged with the screw and a rockable clamp arm is
pivotally connected to the wings of the nut. The clamp arm is
spring biased to an open position and, upon tightening the screw,
the nut is drawn toward the cover plate and the clamp arm is drawn
to a closed position.
It is an object of this invention to provide a readily assembled,
compact clamp assembly for use in securing a cover plate to a
cabinet.
It is a further object of the instant invention to provide a
reliable clamp assembly which is simplistic in operation and
requires no more than the turning of a screw to move the assembly
from a fully clamped position to an open position permitting
removal or installation of the cover plate.
Further objects and advantages will become apparent from the
following description and claims taken together with the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of the clamp assembly
incorporating the principals of the present invention;
FIG. 2 is a perspective view of the clamp assembly in its open
position;
FIG. 3 is a cross-sectional view taken along lines 3--3 in FIG. 2
showing the clamp in its open position and also showing, in
phantom, the clamp moving towards a closed position.
FIG. 4 is a front view of a panelboard including a cover
incorporating the inventive clamp assembly.
FIG. 5 is a front view of a panelboard without the cover with which
the cover and clamp assembly are associated.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 2, 4 and 5 of the Drawings, a panelboard
assembly is indicated by reference character 16. The panelboard
assembly 16 includes a cabinet or box 18 having a cover 20
overlapping the cabinet and retained thereto through the use of
several clamp assemblies 22. As shown in FIG. 5, the box 18 carries
an interior assembly including interior trim 24 as referred to in
U.S. Pat. No. 4,162,517 issued July 24, 1979 to Reed. The interior
trim 24 is behind a door 26 that is hinged to cover 20, as shown in
FIG. 4, to provide access to circuit breakers 23 which may be
connected to the interior assembly without requiring removal of the
cover 20. A lock 27 is provided on door 26 to facilitate operations
and locking of the door with respect to cover 20.
The cover 20 is secured to box 18 by means of a plurality of spaced
clamp assemblies 22 which capture a respective side or lip 28 of
the box between the clamp and the cover. The clamp assemblies are
spaced along the longitudinal side margins of cover plate 20 in
order to securely fasten the cover to the box 18.
A pair of side rabbets 30 and top and bottom rabbets 32 frame the
door opening 34 on the cover 20. The rabbets are generally L-shaped
lengths of metal having one side welded or otherwise connected to
the inside surface of cover 20. The rabbets are associated with
outwardly projecting flange walls or rabbets 25 on the interior
trim 24 as described for example in the Reed patent to resist an
attempt to insert a metal object behind the interior trim 24. Many
different arrangements are feasible for this purpose including
association of single or double rabbets on the cover with
cooperative rabbets or flanges on the interior trim. The rabbets on
the cover, however, restrict the available space for operation of
clamp assemblies which secure the cover to the box. This is
particularly true in a relatively narrow panelboard that may have
less than 3.25 inches between the side rabbet 20 and the sidewall
of box 18. Accordingly the clamp assembly must be compact.
Holes 36 are provided in the cover to facilitate mounting of the
clamp assemblies. Inserted through the hole is an insulating sleeve
member 38 having a head 40 at one end and a pair of diametrically
opposed slots 42 extending from the opposite end of the sleeve
toward the head whereby a pair of opposite crescent portions 44 are
provided on the sleeve that are passed through the hole 36. A nib
46 is provided at the underside of the head adjacent one of the
crescent portions. Nib 46 is received in a notch 48 which is
provided in communication with hole 36 on the cover. Lateral
surface portions 50 of nib 46 abut against portions of the cover
which define the notch to restrain the sleeve member from
rotational movement within hole 36. The head 40 of the sleeve 38 is
provided with a recess 52 which receives the head of a screw member
54. The screw includes a slotted head 56 at one end, a threaded
intermediate portion 58 and a tip 60 at an opposite end having a
reduced diameter from the intermediate portion. A winged swivel nut
62 includes a threaded central portion 64 and opposite wings 66.
The screw 54 is inserted into the sleeve member such that the head
56 is received in recess 52 with tip 60 extending along the
longitudinal axis of the sleeve member past crescent portions 44.
The screw is threaded through the swivel nut 62 with the wings 66
extending radially outward from sleeve 38 through slots 42.
A generally U-shaped clamp arm 68 includes a pair of opposite side
legs 70 joined at a front or clamping end by clamping bridge 72 and
joined at its opposite or camming end by cam bridge 74. The legs of
the clamp arm are dimensioned to provide a rounded camming surface
76 at the camming end which tapers upward towards the clamping end.
A projecting lobe portion 78 is provided which extends downward
from bridge 72 to clamp the lip 28 of box 18 between the clamp arm
and the cover 20.
An opening 80 is provided in each of the leg portions 70 on the
camming side of the leg portion. The openings 80 are aligned to
receive the opposite wings 66 of nut 62. A cutaway portion 82 is
provided on the clamp arm between bridging portions 72 and 74. This
space accommodates receipt of the sleeve member and extending tip
60 of screw 54 when the clamp arm is moved to a fully closed
position. A push-on fastener 84 is pushed over tip 60 to retain the
swivel nut on screw 54.
The clamp arm is biased by spring member 86 to a clamp open
position. Spring member 86 includes opposite coil portions 88 which
are connected by a generally U-shaped bridging portion 90 having
legs 92 and a connecting portion 94. The opposite ends of each of
the coils include an arm 96 with an inwardly bent tang 98 at the
distal end of each arm.
The wings 68 of nut 62 extend respectively through the coil
portions 88 of the spring member which are located on the outside
portion of leg members 70. The inwardly bent tangs 98 are bent
around the underside of respective leg portions 70 adjacent the
lobe portions 78. Connecting portion 94 of the spring abuts against
cover 20 and arms 96 bias clamp arm 68 toward an open position as
shown in FIG. 2.
As shown in FIG. 3, as screw 54 is turned in a tightening
direction, or in this instance to the right, the nut 62 is drawn
toward the cover plate. The screw head cannot pass through stop
portions 100 of sleeve 38 and because wings 66 extend through slots
42, the nut cannot rotate with respect to the sleeve member.
Accordingly, the slots permit the nut to be threadingly drawn along
the intermediate portion of the screw toward the screw head in
response to the tightening rotation of the screw.
As the nut is drawn toward the cover plate, clamp arm 68 is also
drawn toward the cover plate since it is pivotally connected to the
wings of the nut. As the intermediate portion of the clamp arm is
drawn perpendicularly toward cover plate 20, the cam surface 76,
which is biased against the plate, slides a short distance away
from the sleeve as the clamp arm is moved from an open position to
a closed position. The cam surface 76 is accordingly contoured to
permit sliding motion of the clamp arm as the arm is drawn against
the spring bias to a closed position.
While the invention has particularly been shown and described with
reference to a preferred embodiment, it will be understood by those
skilled in the art that variations in form, construction and
arrangements may be made therein without departing from the spirit
and scope of the invention, all such variations are intended to be
covered in the appended claims.
* * * * *